Healthy Cod and Corn Chowder

Name: Healthy Cod and Corn Chowder
Ingredients: 1 tablespoon unsalted butter; 1 tablespoon olive oil; 1 medium yellow onion, chopped; 3 stalks celery, chopped; ½ teaspoon red pepper flakes (optional); 1 sweet red, orange or yellow bell pepper, seeded and chopped; 2 cups young red or yellow potatoes, quartered or halved; 5 cups low-sodium vegetable or chicken stock; 2 cups frozen corn; 1 1/2 pounds cod, cut into 1 inch pieces; 2 scallions, minced; 2 tablespoons parsley, minced; salt and pepper to taste